The disclosed technology relates to lubricants, particularly for internal combustion engines including diesel engines, exhibiting good seal performance and corrosion performance in a low ash formulation.
Lubricants for internal combustion engines are well known. For example, U.S. Pat. No. 6,444,624, Walker et al., Sep. 3, 2002, discloses a lubricating oil composition containing 0 to less than 10% Group I and/or Group II basestocks, a molybdenum additive providing not greater than 1000 ppm of molybdenum to the lubricant, a calcium detergent providing 10 or greater mmoles of surfactant per kilogram of lubricant, one or more other lubricant additives selected from, among others, ashless dispersants, and a viscosity modifier.
U.S. Pat. No. 7,361,629, Loper et al., Apr. 22, 2008, discloses an amination product of a hydrocarbyl-substituted succinic acylating agent and a mixture containing an aliphatic polyamine and an aromatic polyamine. Among the aromatic polyamines disclosed is N-phenyl-1,4-phenylenediamine.
U.S. Pat. No. 4,863,623, Nalesnik, Sep. 5, 1989, discloses an additive composition comprising a graft and amine-derivatized copolymer. It discloses an amino-aromatic polyamine compound from the group consisting of, among others, an N-arylphenylenediamine. A lubricating oil composition containing the same is also provided.
The disclosed technology solves the problems of corrosion and seal degradation in low ash engine lubricants by employing a combination of additives as described herein.